Integral photography

ABSTRACT

Photographs of the integral type, exhibiting the effect of parallax about both horizontal and vertical axes, are recorded on a spherically lenticulated film or a spherically lenticulated screen-film combination by means of a modified type of camera. Light is admitted to the film via a rectangular aperture in the front of the camera instead of via the usual photographic objective. If the camera is held stationary during an exposure, the resulting photograph is pseudoscopic instead of stereoscopic. A feature of the invention is a method, comprising a sequential printing technique, by which the elementary images constituting the composite picture are so transposed that the reproduction is stereoscopic. Another feature of the invention involves lateral movement of the camera during an exposure so that the necessary transposition is accomplished within the camera. Further features of the invention reside in methods of increasing the effective stereoscopic base of the integral photographic system and methods of adapting the system to aerial photography.

United States Patent [72] Inventor Leslie Peter Dudley 10354 WilshireBlvd. Apt. 1, Los Angeles, Calif. 90024 [21] Appl. No. 747,996 [22]Filed July 26, 1968 [45] Patented Oct. 19, 1971 [54] INTEGRALPHOTOGRAPHY 3 Claims, 14 Drawing Figs.

[52] 11.8. C1. 95/18, 95/1 [51] Int. Cl ...G03b 35/08 [50] Field 0!Search 355/33; 350/167; 95/18 P, 1; 88/1 [56] References Cited UNITEDSTATES PATENTS 2,045,129 6/1936 Ferrand 355/33 2,202,354 5/1940 SaintGenies.. 355/33 3,225,651 12/1965 Clay 355/33 3,241,429 3/1966 Rice etal.... 350/167 3,332,775 7/1967 Mandler 350/167 U Primary Examiner-JohnM. Horan Assistant Examiner-D. .1. Clement Attorney-Jessup & Beecher 7ing a sequential printing technique, by which the elementary imagesconstituting the composite picture are so transposed that thereproduction is stereoscopic. Another feature of the invention involveslateral movement of the camera during an exposure so that the necessarytransposition is accomplished within the camera. Further features of theinvention reside in methods of increasing the effective stereoscopicbase of the integral photographic system and methods of adapting thesystem to aerial photography.

I PATENTEDG 1111111 WW W,

PATENTEDUBT 191911 3, 13,539 SHEET'SUF 5 INVHN'IOR 4654 we P6756 pupza ATTOEA/EVS INTEGRAL PHOTOGRAPHY The present invention is concerned withan improved system of stereoscopic or three-dimensional photography. Aphotograph produced in accordance with one or another of the methodsdescribed in this specification exhibits optical characteristics closelyresembling those of a hologram. Thus, the aspect of the recordedthree-dimensional image changes with change of viewpoint about bothhorizontal and vertical axes. However, the new type of photograph, whichmay be appropriately termed an integram or integraph, possesses severalimportant advantages over the hologram. For example, coherent light e.g.laser illumination) is not required in either taking or viewing thepicture. Further advantages are: the photographic equipment employed iscompact and simple to operate; exposure times correspond to those whichwould be required for ordinary two-dimensional photography under thesame conditions; action shots and/or the use of flash present no moredifficulty than with ordinary photography, and it is virtually imposibleto produce an out-of-focus picture.

The photographic record constituting an integram consists of a largenumber of minute, juxtaposed images produced by an optical screen orreseau. The same-or a similar-screen is used when viewing the picture.In the preferred form the screen consists of transparent materialembossed on one surface with an array of small lenticules or lenslets ofspherical or substantially spherical curvature. The screen is so locatedwith respect to the photographic film emulsion or other photorecordingmedium that the photorecording surface is at the focus of thelenticules. A convenient arrangement is for the screen-film combinationto be manufactured as a composite unit, the lenticules being fonned onthe surface of the film base opposite the surface carrying thephotosensitive emulslon.

In some applications of the present invention it is possible to employ,instead of a screen embossed with spherical lenticules, a device whichmay be regarded as the optical equivalent of such a screen. One type ofoptically equivalent screen is made from a pair of cylindricallylenticulated screens, the lenticulated surfaces of the two screens beingin contact with each other, and the longitudinal axes of the lenticulesof one screen being at right-angles to the longitudinal axes of thelenticules of the other screen. Another type of optically equivalentscreen consists, in effect, of a sheet of opaque material pierced with amultiplicity of small apertures disposed in a regular array. In thiscase the apertures are not circular, like a pinhole, but are so shapedthat adjacent images in the corresponding array of images are notappreciably overlapping or spaced apart; thus, apertures of square shapeare very suitable. A satisfactory square-aperture screen can be producedby "crossing" two line screens which have an appropriateopaque/transparent ratio; then, by correct adjustment of the distancebetween the array of apertures and the sensitive surface, matters can beso arranged that adjacent images in the array are not overlapping orspaced apart by an excessive amount. There are, basically, twoalternative techniques either one or the other of which may be used forproduction of an integram; one of these techniques is termed directintegraphy, and the other is referred to as indirect integraphy. Thepresent application is concerned with the direct method, the indirectmethod being described in my copending U.S. Pat. application, Ser. No.747,931, filed of even date herewith, entitled Improvements inStereoscopic Photography." The method described herein resembles thatdisclosed by Gabriel Lippmann in 1908 (C. R. Academic des Sciences, Vol.I46, pp. 446-61). That is to say, the lenticular film or screen-filmcombination is exposed direct without the use of a camera lens. The filmis supported in a suitable camera body or holder during exposure. Theexposure is controlled by the use of a filter or filters in front of thefilm and (or) by adjustment of the shutter speed, the shutter beingpreferably of the focal-plane type.

A minute image of the entire scene is recorded in the format of eachlenticule, but the aspect of the scene represented by each such image isdependent upon the location of the associated lenticule with respect tothe other lenticules in the array. Upon viewing the completedphotograph, through the lenticular array, the eyes perceive the opticalreconstitution or integration of the multiplicity of images whichexhibits the form of a single, three-dimensional image. The degree ofparallax exhibited by the three-dimensional image, about the horizontaland vertical axes, is governed by the corresponding dimensions of theformat of the screen-film combination. A photograph produced in thesimple manner just indicated, as in the case of one produced inaccordance with Lippmann's proposal, will be seen in pseudoscopic reliefinstead of stereoscopic relief. It is a feature of the present inventionto provide means whereby this defect can be overcome so that theresulting picture exhibits stereoscopic relief and is correctlyoriented. Other features of the invention will become apparent later inthe specification.

Nature of the Lenticules and Method of Manufacture In the applicantscopending U.S. Pat. application, Ser. No. 747,931, referred to above,there is a detailed discussion of the optical properties of theindividual lenticules and methods of manufacturing lenticular film andscreens suitable for use in connection with the invention. Such film andscreens are also suitable for use in connection with the inventiondescribed herein. However, it is generally desirable for lenticulesdesigned for use in the direct method to have a greater acceptance anglethan those used in the indirect method. In the case of the directmethod, the angular coverage of the photographic system is limited byand to the acceptance angle of the lenticules. 0n the other hand, in thecase of the indirect method, the angular coverage of the system isgoverned solely by that of the camera lens. Thus, the angular coveragecan be varied by the simple expedient of changing the lens. In mostpractical cases the angular coverage of the lens is in excess of theacceptance angle of the lenticules.

In the drawings:

FIG. 1 is a simplified diagram representing a piece of sphericallylenticulated film recording an integral photograph.

FIG. 2 is a perspective view representing a piece of sphericallylenticulated film recording an integral photograph.

FIG. 3 shows the piece of film in FIG. 2, viewed through the lenticules,subsequent to processing and being rotated through in the image plane.

FIG. 4 represents a contact (emulsion-to-emulsion) print from theoriginal photograph in FIG. 3.

FIG. 5 represents one type of print which can be obtained, by means of atwo-stage transposition proces, from the original photograph in FIG. 3.

FIG. 6 represents a further type of print which can be obtained, bymeans of a single transposition process, from the original photograph inFIG. 3.

FIGS. 7 through 10 constitute a series of diagrams illustrating theprinciple of the transposition process.

FIG. 11 shows a form of camera suitable for taking photographs inaccordance with the invention.

FIG. 12 is a diagram showing an optical method of extending thestereoscopic base of an integral photographic system.

FIGS. 13a and 13b are diagrams showing mechanical methods of extendingthe stereoscopic base of an integral photographic system.

BASIC PRINCIPLE FIG. 1 is a simplified diagram representing a piece ofspherically lenticulated film (or screen-film combination) F recordingan integral photograph of an object 0. As will be understood, thelenticules are shown greatly enlarged for the sake of clarity. It is tobe assumed that the diagram represents a plan view, the left and rightedges of the object being denoted by respectively I and r, thecorresponding edges of the film being denoted by l and r. It will beobserved that the aspect of the little image formed at the focus of eachlenticule is dependent upon the location of the lenticule relative tothe object, the aspect changing progressively from an extreme leftwardview at the edge I of the film to an extreme rightward view at the edger. In addition to the single row of lenticules illustrated, there are,of course, further, parallel rows of lenticules which must be imaginedas disposed in a plane normal to the surface of the drawing.Accordingly, the images recorded by the lenticular array differ inrespect of both vertical and horizontal parallax.

Let us now imagine that the processed film is viewed by an observerlocated in front of the lenticules at some position such as thatoccupied by the object O in FIG. I. Then the leftward aspects of theimage will lie to his right and will be seen predominantly by his righteye, while the rightward aspects will lie to his left and will be seenpredominantly by his left eye. In consequence, the integral image willbe seen pseudoscopically. It will also appear upsidedown or invertedrdueto the inversion of each little image element resulting from the actionof the associated lenticule. If, now, the piece of film be rotatedthrough l80 in its own plane in order to compensate for this inversion,the integral image will be laterally inverted or perverted so that itwill again be seen pseudoscopically. In short, in order that thecompleted photograph may be seen in stereoscopic relief, it is necessaryfor the individual picture elements to be appropriately reoriented ortransposed. The situation is similar to that prevailing when a simplestereogram or stereoscopic pair of photographs has been recorded on asingle plate or piece of film; the two views, or reproductions thereof,must be laterally transposed in order that they may be viewed instereoscopic relief in a stereoscope.

, In order that the integral image shall appear sharp, clear andundistorted, it is necessary to provide means for avoiding the formationof secondary or parasitic images. One such means is to arrange, in themanufacture of the lenticular film or other screen-film combination, foreach lenticule to be isolated from the adjacent lenticules by asurrounding boundary composed of some opaque substance. This substancemay take the form of a photographic emulsion, applied to thelenticulated surface in a thin vlayer so that it surrounds, withoutcompletely covering, the lenticules. The layer is then exposed to lightand chemically developed in order to render it both black and opaque. Aswill be understood, this stage of the manufacturing process is carriedout prior to application of the photorecording layer or layers in thosecases in which the lenticular screen isan integral part of the film. Anopaque layer of this type is represented in FIG. 1 by the dark areasbetween the lenticules. As an alternative, or in addition, to the use ofsuch a layer, it is possible to use a lightshield or hood extendingoutward from the edges of the film format.

The Transposition Process -the extreme rightward aspects; Nos. 1, 2, 3and 4 represent the extreme upper aspects; Nos. 13, l4, l5 and I6represent the extreme lower aspects, and Nos. 6, 7, l0 and 11 representintermediate aspects, as will be understood. If the processed film,erected in order to compensate for the image-inversion due to the actionof the lenticules, is now viewed through the embossed surface, theorientation of the elementary images will be as shown in FIG. 3; thus,the images will be laterally inverted or perverted, in consequence ofwhich the integral image will be pseudoscopic. A further point, but oneof minor consequence, is that the effect of vertical parallax will beexhibited in a manner opposite to that occurring in everyday visualexperience. This is due to the interchanging of the horizontal rows ofimages as indicated in the drawing. A contact (emulsion-to-emulsion)print from this photograph onto a second, matching piece of lenticularfilm will bring about the result represented by FIG. 4. In this case theintegral image will again be pseudoscopic since, although eachindividual elementary image is correctly oriented, theleftward aspectsare located to the right of the observer, and the rightward aspects arelocated to his left. Vertical parallax will be exhibited in the samemanner as by the arrangement show rr in FIG'. 3., Clea rly, the ideal orperfect solution to this problem would be provided by (a) rotation ofeach elementary image through I80'within its own format, followed by (b)the making of a contact (emulsion to-emulsion) print.- This would yieldthefarrangeinent shown imFIG. 5, resulting in an integral image whichisstereoscopic and free of error in respect of vertical parallax. However,as discussed at length in the applicant's copending US. Pat.application, Ser. No. 747,931, it is a demonstrable fact thatstereoscopic photographs which exhibit reversed vertical parallax areentirely acceptable to the observer; indeed, this type of defect willgenerally pass completely unnoticed. Thus,

'the arrangement of the elementary images which is represented in FIG. 6also constitutes a satisfactory integram, as the resulting integralimage is correctly oriented and stereoscopic. Means whereby integrams ofthe types represented in both FIGS. 5 and 6 can be produced constitutefeatures of the presentinvention.

The transposition process with which the invention is concerned involvesa sequential printing technique which can be followed with the aid ofFIGS. 7 to 10. These four schematic drawings represent a time-spacedsequence of steps by which the original integral photograph in FIG. 3can be used to print the integram represented in FIG. 6.

Referring to FIG. 7, the original photograph, denoted by O, is placed inemulsion-to-emulsion contact with the matching piece of lenticularmaterial P on which the reproduction is to be printed, the left-handcolumn of lenticules on 0 being opposite the right-hand column oflenticules on P. The general direction of the printing light rays isindicated by the arrow A. The width of the strip of emulsion beingexposed is restricted to the lenticular pitch distance; this can beaccomplished by any suitable means, such as by admitting the light via anarrow slit, narrow cylindrical lens, or other convenient arrangement.Thus, in FIG. 7, just those images numbered l6, l2, 8 and 4 are printed.Referring now to FIG. 8, it will be noted that the photograph 0 has beentransported to the left through a distance equal to the lenticularpitch, and that the film P has been transported to the right through thesame distance; accordingly, the images numbered 15, ll, 7 and 3 can nowbe printed to the left of the column of images first reproduced. In FIG.9 the two pieces of photographic material are depicted as having beenagain transported, in opposite directions, through a distance equal tothe lenticular pitch, making it possible for the third column of imagesto be printed. FIG. 10 shows, finally, the printing of the fourth andlast column of images, the completed integram now being of the typerepresented in FIG. 6.

The foregoing method of accomplishing the desired result has beenselected for description simply as an example of the general principleinvolved. Various modifications of the technique are possible. Theessential feature is that, between successive steps in the printingoperation, there must be relative movement between the two films, platesor the like through a distance equal to twice the lenticular pitch.Accordingly, it is not necessary for both pieces of photographicmaterial to be transported laterally. Thus, the piece denoted by P inthe diagrams can be held stationary while that denoted by 0, togetherwith the printing aperture or equivalent, is

transported laterally through twice the distance(s) indicated in thepreceding explanation of the process. In the method preferred by theapplicant, the piece of photographic material 0, together with theprinting aperture, is held stationary while the piece of photographicmaterial P is transported.

If desired, the aforementioned relative movement between the two piecesof photographic material can be intermittent, printing light beingadmitted only during the stationary periods. However, the applicantconsiders it to be more practical and convenient for the movement to becontinuous; the light source (e.g., electronic flash) is so synchronizedwith the film transport mechanism that a light pulse is emitted eachtime the film has moved through the prescribed distance. Provided thatthe duration of a pulse is asmall fraction (e. g., onehundredth) of thetime taken by a lenticule to move past the printing aperture, noperceptible image-smear will result. As an alternative to electronicflash, a source of continuous illumination can be employed, the lightbeing occultedintermittently by means of a synchronously driven shutter,or switched on and off by a synchronously operated commutator device.

By repeating the transposition process, but using a vertical scaninstead of the original horizontal scan, an integram of the type shownin FIG. (or FIG. 6) can be converted into one of the type shown in FIG.5. However, for the reason previously indicated, this second scanningoperation is considered to be unnecessary in the majority of practicalapplications of the process.

No basically new mechanism is required in order to accomplish thetransposition process. The accurate transport mechanism which isnecessary is available in, for example, ruling engines of the types usedfor producing fine-pitch line screens and diffraction gratings. (Aportion of a typical ruling engine, modified for the manufacture ofspherically embossed lenticular film, is illustrated in the applicantscopending U.S. Pat. application, Ser. No. 747,931.) To one skilled inthe art, the provision of the necessary light-tight enclosure, filmplatens, illuminating means, etc., will not present difficulty.

Copies of integrams of the types represented in FIGS. 5 and 6 can bemade by any of the techniques described in the patent applicationmentioned above.

Camera for Recording Integral Photograph FIG. 11 shows an example of aninstrument for use in image-recording in accordance with a feature ofthe invention. This can be either an instrument designed specificallyfor the purpose or, alternatively, a regular camera which has beenappropriat'ely modified.

Although no camera lens is used, it is necessary that the equipmentemployed shall embody certain physical and mechanical features which arecommon to the majority of regular photographic cameras. The mainfeatures which are considered to be essential are the following: ahousing (e.g., camera body), container or film holder for supporting thefilm or other photosensitive material during image-recording, and forprotecting said material from unintentional exposure to light; somemeans (e.g., variable-speed focal plane shutter) of admitting acontrolled amount of light from the subject to the photosensitivesurface via the lenticules; means (e.g., film-advance mechanism or a setof cut-film holders) for bringing a fresh, unexposed area ofphotosensitive material into position after an exposure has been made,and some form of viewfinder.

Consider now that the sketch of FIG. 11 represents a camera, designedoriginally for use with 35 mm. or, say, 2%, inch-wide roll film. Assume,further, that the camera is equipped with a focal plane shutter,actuated by the shutterrelease button 4. The film-advance andshutter-cocking lever is denoted by the numeral 1 in the sketch, 2denotes the shutter speed-adjustment knob, 3 denotes the viewfinder, and5 denotes the film-rewind knob and lever. (The latter control is, ofcourse, required only if cassette-loading is employed.) As will benoted, the camera lens has been removed, and it is to be assumed that arectangular aperture 0 b c d has been cut in the front of the camerabody. The width (major dimension) of this aperture is preferably aboutequal to the length of that portion of film which extends between thetwo spools and is held flat in the focal plane. Thus, the width can beassumed to be somewhat greater than that of the picture format for whichthe camera was originally designed. For the sake of simplicity, it willbe assumed that the width is equal to twice that of the original format.

In the example arrangement illustrated, two equal rectangular portionsat the left and right sides of the aperture have been closed by theinsertion of a pair of opaque plates 6 and 10. These plates can beeasily removed, when required, for a purpose to be described later. Afurther, larger plate 7 is inserted between plates 6 and 10, arectangular or square aperture 8 having been cut in the center portionof this larger plate. The dimensions of this aperture are substantiallythe same as those of the original format. Into this aperture is inserteda thin walled, framelike component 9 which protrudes outward from thecamera body for a short distance and inward so that the rear edges arein contact with a sheet of clear glass. This sheet of glass, thesurfaces of which are preferably optically coated, extends over theentire area bounded by the rectangle a b c d. The purpose of the glassis to protect the shutter, film, etc., against ingress of dust or otherextraneous matter. The portion of the frame 9 which protrudes outwardfrom the camera body can, if desired, be slotted to receive filters ofvarious types, such as color filters, polarizing filters, etc. Anadditional, desirable accessory, denoted by 11 in the sketch, is a sunshield designed for fitting around, and attachment to, the front portionof the frame 9.

Modified as shown in FIG. 11, the equipment is now adapted forrecording, on suitable spherically lenticulated film, integralphotographs each of which will be constituted of an array of microscopicimages extending over an area of film corresponding to that of theoriginal format. As will be understood, the magnitude of thethree-dimensional effect will be governed by the dimensions-primarilythe horizontal dimension-of that format. Now, in the case of a camera ofthe type illustrated, the length of that dimension will generally beless than 21/2, inches, so that the three-dimensional effect will beless than normal. However, the stereoscopic base can be increased, ifdesired, with the aid of the removable plates 6, 7 and 10 in the mannernow to be described.

On the basis of the assumption, made previously, that the horizontaldimension of the rectangular aperture 4 b c d is equal to twice thewidth of the original format, it follows that removal of plates 6, 7 and10 will double the length of the strip of film exposed when the shutteris actuated. Accordingly, the amount of horizontal parallax, and hence,the three-dimensional effect, will also be doubled. The number ofexposures that can be made on a given length of film will, of course, behalved. If the instrument employed is a regular camera which has beenmodified, rather than an instrument which has been designed specificallyfor the present purpose, there are some further points to be borne inmind if the feature just described is to be utilized. For example, thewidth of the gate aperture will generally have to be increased; so, too,will the distance traversed by the focal plane shutter. Another pointrelates to the feature-common to many so-called miniature andsmallformat cameras which provides interlocking of the film-advance (andshutter-cocking) lever and the shutter-release button. The interlockingmechanism prevents double exposure on a single frame of film, and alsoobviates film wastage by preventing the operator from advancing afurther frame of film into position until the shutter-release button hasbeen pressed. Hence, in order to make a series of exposures each ofwhich occupies a length of film equivalent to two regular frames, we canadopt one or the other of two procedures. One of these procedures is tomodify the mechanism in such a way that the film-advance and shuttercontrols can be operated independently; the film can then be advancedthrough the required distance equal to the width of two regular frameswithout the necessity for pressing the shutter-release button after thefilm has moved through one-half of that distance. The other, moresimple, procedure involves no modification to the camera mechanism; itinvolves merely the provision of an opaque mask or blind for occultinglight from the aperture a b c d when, afler the film has moved throughone-half of the total required distance, actuation of the shutter isrendered necessary by the interlocking mechanism. Just as it isdesirable for a frame 9 and sun shield ll to be employed in conjunctionwith the small aperture 8, so, too, is it desirable for a larger,

appropriately shaped frame and sun shield to be used in conjunction withthe aperture a b c :1. With the plates 6 and 10 in position, asindicated in the sketch, but with the plate 7 removed, it will beevident that the area of film occupied by each exposure is greater thanthat of the original format but less than that of the aperture a b c d.It is, of course, desirable for an appropriately shaped frame and sunshield to be used in conjunction with this intermediate-sized aperturealso.

If an intermediate-sized aperture, as indicated above, is to beemployed, it is preferable for the entire apparatus to be speciallydesigned; in modifying a regular camera to include I this feature, it islikely that problems will arise in connection with the film transportmechanism, frame counter, etc.

Use of Auxiliary Optical System FIG. 12 is a schematic diagram showinghow the stereoscopic base of an integral photographic system can beextended beyond the limit imposed by the dimensions of the film or imageformat.

Referring to the sketch, S denotes a spherically lenticulated screen thetransverse dimensions of which are relatively large compared with thoseof the image format F. The screen forms a multiplicity of small images,at its focal plane, of the complete scene or subject. This array ofimages is reproduced, to a reduced scale, in the format F of the lens L,It is preferable for a field lens L, to be located at, or in closeproximity to, the focal plane of the screen S. As will be understood,the image-recording medium at F may be photographic film, thephotosensitive face of a television camera tube, or any other type ofimage recording or image-receiving medium.

Use of an auxiliary optical system, in the way indicated above, does notchange the nature of the integral image from pseudoscopic tostereoscopic; this is because introduction of the lens L,, with orwithout the field lens L simply causes inversion of the array ofelementary images as a whole, and does not cause inversion of eachelementary image within its own individual format. Hence, transpositionof these images must still be accomplished by, for example, thesequential printing process described earlier in the specification As analternative to that process, an electronic scanning technique or itsoptomechanical equivalent (i.e., scanning by means of a lightspotinstead of an electron beam) can be employed. Transposition by scanningis particularly useful in television applications of the invention.Thus, an image formed in, say, the upper left-hand comer of the fonnatof a television camera can be reproduced, after transmission to atelevision receiver, in the corresponding corner of the picture tube orin any one of the other three comers, depending upon the arrangement ofthe scanning circuitry. As will be understood, the faceplate of thepicture tube of the receiver must be embossed with lenticulesdistributed in an array which corresponds with the lenticular array usedin transmission. This matter and related topics are discussed in moredetail in the applicants copending patent application to which previousreference has been made.

Referring, once more, to FIG. 12, when the image format at F is that ofa television camera tube, it is, of course, unnecessary for thefaceplate to be lenticulated. If, however, the format at F is that of apiece of photographic film or the like, the material may be eitherlenticular or nonlenticular depending upon the manner in which it is tobe treated after'exposure and processing. For example, assuming aregular photographic plate is employed, the orientation of theelementary images recorded will be as shown in the earlier diagram FIG.3. These images can then be reoriented, by the transposition processalready described, in the way shown in FIG. 5 or that shown in FIG. 6. Asuitable, matching lenticular screen can then be laminated to thisreproduction so that the picture can be seen in stereoscopic relief. If,on the other hand, a piece of lenticular film is placed at F, thelenticules on the film matching, to an appropriately reduced scale,those on the screen S, the transposition process is renderedunnecessary. This is due to the fact that the additional image-inversioncaused by the lenticules on the film results in the elementary imagesbecoming oriented as represented in FIG. 5. However, this is difficultto accomplish in practice owing to the high degree of precision withwhich it is necessary for the lenticules on the film to be matched withthose on the screen S.

Mechanical Amplification of Stereoscopic Base, 7

In the applicant's U.S. Pat. No. 2,572,994 (corresponding to BritishPat. No. 656,165) there is a description of a type of camera mounting sodesigned that a camera supported thereon can be moved laterally througha predetermined distance during the exposure period. This mounting isintendedprimarily for use in the taking of stereoscopic photographsofthe type known as-parallax panoramagrams. However, a mounting of thisnature, or a simplified form thereof, can be usefully adapted to form afeature of the present invention as described below.

FIG. 13a is a schematic plan view representing a piece of lenticularfilm L being exposed to light entering through the vertical slit S in afocal-plane shutter F. The angular field of the lenticules is denoted by0. It is to be imagined that the film and shutter are contained within asuitable piece of photographic apparatus or camera as discussed earlierin the specification. It is to be assumed, further, that the apparatus,supported on a suitable mounting, is transported laterally from positionI to position II during the time taken by the shutter slit to traversethe width of the film fonnat. In this pair of diagrams the film andshutter slit are depicted as moving in the same direction. Inconsequence, extreme leftward images of the scene are recorded on theleft-hand edge of the film,and extreme rightward images .are recorded onthe right-hand edge, just as if the film had. remained stationary-duringexposure. However, the horizontal parallax. or stereoscopic base hasbeen increased by an amount equal to the distance through which the filmhas moved. In the example illustrated, the width of the film is denotedby w, and the distance through which it has moved amounts to 3w; hence,the stereoscopic base has been increased from w to 4w. The orientationof the elementary images is as indicated in the earlier diagram, FIG. 2,so that the integral photograph is pseudoscopic. Hence, in order toproduce an integram of the type represented in FIG. 6, transpositionabout one axis must be performed. If an integram of the type representedin FIG. 5 is required, transposition must be performed about two axes.

FIG. 13b is a diagram similar to FIG. 13a, but in this case the film andthe shutter slit are represented as moving in relatively oppositedirections. As a result of this arrangement, extrerne leftward views ofthe scene are recorded on the righthand edge of the film, and extremerightward views are recorded on the left-hand edge. In this case, theresulting stereoscopic base is equal to the distance through which thefilm has moved minus the width of the film, amounting, in the exampleillustrated, to 3-w==2w. An important consequence of this type ofarrangement is that a contact (emulsion-toemulsion) print from theoriginal photograph results in the production of an integram of the formpresented in FIG. 6, transposition about the horizontal axis having beenalready accomplished during the photographic operation. Furthertransposition, about the vertical axis, results in the production of anintegram of the type represented in FIG. 5;

With photographic systems of the type under discussion it is necessaryto ensure that no perceptible image-smear results from the lateralmovement of the film. The principal requirements are: I

l. The parallax angle should not be exeessive,generally not more thanabout 15 to 25 in the case of the nearest foreground object. That is tosay, the angle subtended at any point in the scene or subject by thetotal stereoscopic base line should not be greater than about 15 to 25.

2. The slit in the focal plane shutter should be narrow,- generally notwider than the lenticular pitch distance, although the slit may have awidth in excess of this limit if the parallax angle is small and thelenticular pitch is fine.

Aerial Photography The principle described in the preceding section canbe usefully applied to integral photography from a moving vehicle, suchas an aircraft or a spacecraft. In this case, however, the mountingreferred to above is not required, the translatory movement of the filmrelative to the subject (e.g., terrain) being effected by the forwardmotion of the vehicle. It is preferable for the photographic equipmentto be supported in a mounting which pivots in such a manner that,throughout the exposure period, an imaginary straight line extendingfrom the center of the film format, and normal to the surface thereof,passes through substantially the same point in the target or scene beingrecorded. The mounting can be stabilized, by methods known to thoseconversant with the art, to minimize the effects of undesired motion ofthe vehicle, such as pitch, roll and yaw.

The direction of motion of the focal plane shutter slit should besubstantially parallel to the flight axis. Further, in-order that thefilm may be viewed stereoscopically, and not pseudoscopically,immediately after processing, the shutter slit should move in adirection opposite to the direction of flight.

Having fully described my invention, it is to be understood that I amnot to be limited to the details herein set forth but that my inventionis of the full scope of the appended claims.

I claim:

l. A photograph of the integral type comprising backing means supportingan image-recording layer on which is recorded an array of elementaryimages of different aspects of the same scene, the aspect of the scenerepresented by each such elementary image being dependent upon thelocation of that image with respect to the others in the array, theindividual elementary images being so positioned that, whereas each suchimage is correctly oriented with respect to its horizontal and verticalaxes, and whereas the images are arranged in sequence along thehorizontal axis of the array so that those images corresponding to moreleftward aspects of the scene are reproduced in the left-hand portion ofthe array and those images corresponding to more rightward aspects arereproduced in the right-hand portion of the array, the said images arearranged in sequence along the vertical axis of the array so that thoseimages corresponding to upper aspects of the scene are reproduced in thelower part of the array and those images corresponding to the loweraspects of the scene are reproduced in the upper part of the array.

2. The photograph claimed in claim 1, and which includes a transparentviewing screen applied to the surface of said photograph, the viewingscreen having lenticules of substantially spherical curvature formed onthe front surface thereof, the rear surface being in contact with theimage-recording layer, the said image-recording layer being locatedsubstantially at the focal plane of said viewing screen.

3. The photograph claimed in claim 2, and which comprises a compositestructure, the image-recording layer being a photosensitive layerapplied to one surface of a transparent photographic film base theopposite surface of which has spherical lenticules formed thereon.

1. A photograph of the integral type comprising backing means supportingan image-recording layer on which is recorded an array of elementaryimages of different aspects of the same scene, the aspect of the scenerepresented by each such elementary image being dependent upon thelocation of that image with respect to the others in the array, theindividual elementary images being so positioned that, whereas each suchimage is correctly oriented with respect to its horizontal and verticalaxes, and whereas the images are arranged in sequence along thehorizontal axis of the array so that those images corresponding to moreleftward aspects of the scene are reproduced in the left-hand portion ofthe array and those images corresponding to more rightward aspects arereproduced in the right-hand portion of the array, the said images arearranged in sequence along the vertical axis of the array so that thoseimages corresponding to upper aspects of the scene are reproduced in thelower part of the array and those images corresponding to the loweraspects of the scene are reproduced in the upper part of the array. 2.The photograph claimed in claim 1, and which includes a transparentviewing screen applied to the surface of said photograph, the viewingscreen having lenticules of substantially spherical curvature formed onthe front surface thereof, the rear surface being in contact with theimage-recording layer, the said image-recording layer being locatedsubstantially at the focal plane of said viewing screen.
 3. Thephotograph claimed in claim 2, and which comprises a compositestructure, the image-recording layer being a photosensitive layerapplied to one surface of a transparent photographic film base theopposite surface of which has spherical lenticules formed thereon.